A few years ago the mobile phones were both expensive and unusual, and therefore the possible detrimental effects of the mobile phones were not in focus. Today, the latter attitude has changed, among other things because the majority of the population in many countries own both an ordinary land based phone at home and a mobile phone to take with them. Therefore, the question has been raised whether or not the electromagnetic radiation from the mobile phone can optionally have a detrimental effect on the body tissue, i.e. not only the radiation transmitted by the transmitter and the antenna, but also the radiation from the remaining components of the mobile phone, such as the microprocessor, the display etc.
The radiation from the transmitter and the antenna of the mobile phone is identical with the radiation used in a microwave oven for heating articles of food, and accordingly it is obvious that such a radiation does have an effect on various types of body tissues. However, the frequencies, the radiation intensities and the radiation length having the detrimental effect are not evident. Tests have shown that a highly intense radiation at specific frequencies can cause cellular changes which in turn can result in for instance development of cancer or fetus deformities. However, such clear indications are only found at relatively strong effects, but assumptions are made that effects at a considerably lower radiation intensity for a long period can result in diseases and damages as well. However, no specific indication has yet been found of the detrimental frequencies, the detrimental radiation levels and the detrimental radiation lengths. However, there is a general agreement that a possible reduction of the radiation level is likely to have a beneficial effect in the long run.
Many devices for shielding against radio radiation and other types of radiation from mobile phones are known. These devices can be classified according to the structure of the shielding.
A first class deals with devices for shielding existing mobile phones. WO 02/095867 A1 describes for instance a number of such devices. One of these devices is in form of a box or a bag in which the mobile phone is placed, and where the box or the bag is made of a material possessing shielding properties, such as a metallic fabric or plate elements. The placing of the mobile phone in such a bag or such a box renders it possible to shield against most of the transmitted electromagnetic radiation. Accessories are also described, such as for instance particularly structured hats or glasses rendering it possible to insert a length of shielding material between the mobile phone and the ear of the user when the mobile phone is used. The latter material must necessarily be penetrable by sound waves. Other publications, such as for instance JP 11-261271, describe how the cover of a mobile phone can be provided with a thin layer shielding against the electromagnetic radiation.
DE 201 03 737 U1 discloses a device made of at least 30% of precious stones, semi-precious stones or crystal, where the device is arranged adjacent a radiation source so as to limit the electromagnetic radiation.
Other devices for reducing the radiation involve means arranged in or about the transmitter of the mobile phone or in and about the antenna of said mobile phone with the result that the radiation from the mobile phone in a specific direction, such as towards the head of the user, differs significantly from the radiation in another direction, such as away from the head of the user. Such devices can for instance be shielding devices of the type described in GB 2350725 A, where said device is arranged between the transmitter of the mobile phone and the side of said mobile phone facing the user during ordinary use. Such devices can be formed by a shield possessing ordinary, shielding properties. Other patents, such as GB 2336035, describe units which are secured to the antenna of a mobile phone, and which change the form of the radiation field about the antenna of the mobile phone in such a manner that the radiation towards the head of the user is reduced.
Finally, according to GB 2350482 A the position of the antenna can be changed relative to the position ordinarily used in connection with mobile phones in such a manner that it is directed away from the user and further such that the field adjacent the head of the user is thereby reduced. Mobile phones are also described where a particular antenna design changes the intensity of the radiated field about the mobile phone.
The above solutions and other solutions of such a nature do more or less change the radiation that the user of a mobile phone is subjected to. The described techniques are, however, encumbered with a number of draw-backs. The main purpose of a mobile phone is indeed that it is portable, i.e. it is so small that it can fit in a bag or a pocket and is light. In addition, it must be possible to use the mobile phone in a way not bending, braking or damaging the shielding equipment. Some solutions place the mobile phone inside a shielding device, and such shielding devices are likely to shield well against the radiation. However, such shielding devices increase the size and the weight of the mobile phone as well and results in a reduced user-friendliness of the mobile phone. Correspondingly, several devices are secured in and about the transmitter or on the antenna, and they do indeed shield the user against radiation, but these devices also make the mobile phone rather unhandy and increase possibly the weight thereof with the result that the user-friendliness of the mobile phone is reduced. It is of vital importance that the properties of the transmitter/receiver in the mobile phone are not changed significantly.
All the above solutions include more or less the so-called conventional shielding means for shielding a mobile phone, i.e. metallic devices of an electrically conducting material and/or a ferromagnetic material known to possess good properties with respect to shielding against radiation. However, yet another possibility exists of shielding for instance mobile phones against radiation.